This invention relates to a rope locking device and, more particularly, to a rope locking device for stopping an abnormal descent of an ascending and descending apparatus such as a gondola or the like apparatus used for a construction work etc. when such apparatus descends at an abnormally high speed due to a trouble in a winch or other cause.
As a rope locking device for stopping an abnormal descent of a gondola or the like due to a trouble of a winch, there have been known devices as disclosed in Japanese Preliminary Utility Model Publication Nos. 12529/1980 and 189986/1982. In these locking devices, a pair of wedge-shaped members each having a groove which fits with a rope in the inner portion thereof and having a tapered outer surface are disposed symmetrically in a single case, guide blocks are provided outside of these wedge-shaped members which guide blocks are in contact with the tapered surfaces of the wedge-shaped members so as to guide these wedge-shaped members, and an actuating device is also provided to actuate the wedge-shaped members. In emergency, these wedge-shaped members are actuated to clamp the rope from both sides and thereby stop the abnormal descent of the gondola or the like apparatus.
There has recently been proposed a system for operating a gondola or the like ascending and descending apparatus (hereinafter referred simply to as "gondola") in which, for improving safety and stability of the gondola, a rope locking device is mounted not only to a rope suspending the gondola but also to a rope or ropes which are stretched vertically at suitable sites such as either side of the gondola and are used for a work other than suspending the gondola. According to this system, the rope for work other than suspending the gondola is utilized as an auxiliary rope for enhancing safety and stability of the gondola. In carrying out this method, however, the above described prior art rope locking device has been found to have a serious disadvantage. In mounting such prior art locking device to a rope, one end of the rope is inserted from one of two rope insertion openings formed in the top and bottom portions of the case of the locking device and taken out of the other rope insertion openings. When this prior art locking device is used for a rope for suspending a gondola, a free end portion of the rope suspended from a parapet wall hook is inserted through the locking device mounted on the gondola on the ground and thereafter the free end of the rope is connected to a winch provided in the gondola. In this case, no particular disadvantage arises. However, in a case where this rope locking device is used for utilizing a rope used originally for a work other than suspending the gondola as an auxiliary rope for ensuring safety and preventing horizontal sway of the gondola, the rope which has already been fastened firmly to a fastening device placed on the ground by using a rope tightening machine must be released from the fastened state to insert the released free end of the rope through the locking device and then the rope must be fastened to the fastening device again ( because the rope must be stretched tightly for preventing horizontal sway of the gondola). This apparently involves a great deal of extra labor. A great difficulty is particularly felt in such a case as when a work is done while the gondola is moved horizontally from one site to another along a wall surface of a building. It is extremely difficult to mount and dismount the rope locking device in air from one rope to another among ropes stretched vertically and in parallel to each other.
It is, therefore, an object of the invention to provide an improved rope locking device eliminating the above described problem arising in using the prior art rope locking device for the method of operating a gondola utilizing ropes used originally for a work other than suspending the gondola. More specifically, it is an object of the invention to provide a rope locking device which can be mounted to or dismounted from a rope which has already been stretched between the roof of a building and the ground without releasing the rope from a fastened state.